Modern vehicles contain numerous electronic and electrical switches. Vehicle features such as climate controls, audio system controls, windshield wiper controls, front and rear window temperature controls and the like are now activated, deactivated and adjusted in response to electrical signals generated by various switches in response to driver/passenger inputs, sensor readings and the like. These electrical control signals are typically relayed from the switch to the controlled devices via copper wires or other electrical conductors. Presently, many control applications use a single wire to indicate two discrete states (e.g. ON/OFF, TRUE/FALSE, HIGH/LOW, etc.) using a high or low voltage transmitted on the wire. Alternatively, analog signals may be provided as continuous inputs to potentiometers or the like found in such devices as pedal position sensors, throttle plate position sensors and/or the like.
As consumers demand additional electronic features in newer vehicles, the amount of wiring present in the vehicle continues to increase. This additional wiring occupies valuable vehicle space, adds undesirable weight to the vehicle and increases the manufacturing complexity of the vehicle. There is therefore an ongoing need in vehicle applications to reduce the amount of wiring in the vehicle without sacrificing electronic features. Further, there is a need to increase the number of electronic functions in the vehicle without the additional weight, volume or complexity of additional wiring.
Accordingly, it is desirable to formulate systems and techniques for increasing the amount of control data that can be provided across a single electrical conductor. Moreover, there is a desire to create switching circuits capable of providing more than two data states across a single conductor. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.